Crawler tread



Sept 11, 1962 F. E. TRUDEAU 3,053,579

CRAWLER TREAD Filed Dec. 1. 1960 2 Sheets-Sheet 1 FIG. 2.

F. E. TRUDEAU CRAWLER TREAD Sept. 11, 1962 2 Sheets-Sheet 2 Filed Dec. 1, 1960 United States Patent Ofi ice 3,053,579 Patented Sept. 11, 1962 ware Filed Dec. 1, 1960, Ser. No. 72,923 6 Claims. (U. 30557) This invention relates to crawler treads of the type which are connected together to provide an endless series of shoes providing a track upon which crawler excavators travel.

The usual type of crawler track, because of the conditions under which it operates is subjected to much abuse and frequently wears to the point that retreading is required. In that case, one or more complete crawler units must be disconnected and complete new ones inserted. Since the worn unit must be scrapped, this becomes an economic waste. Moreover, the time required for renewals and adjustments not only takes the excavator out of service and for that reason the down-time often becomes more costly than the track itself.

While tread units wear not only on their ground engaging faces, nevertheless the zone of greatest wear is at the point or points engaged by the driving tumblers and crawler rollers. \Normally the treads and sprockets operate in various kinds of earth which have highly abrasive characteristics so that the part of the tread which takes the greatest punishment is that portion where the drive tumblers or rollers engage therewith. This localized zone of wear requires many treads to be renewed even though the ground engaging portions and the pivots, still have useful life.

Accordingly, a primary object of the invention is to provide a crawler tread with :a renewable roller path and drive lug insert. That is to say, the present invention has in view a crawler tread whose medial area is formed at the time of casting with a socket or recessed portion which receives the shank or stem of renewable roller path and driving lug section which bears the full weight of the excavator or other machinery and yet may be readily removed and replaced without completely taking apart the track, thereby minimizing shutdowns and at the same time augmenting the general longevity of the tread.

Another object of the invention is to provide a tread unit which may be readily cast in two parts, namely a tread proper and a load bearing renewable roller path unit so that the latter carrying the lugs may be replaced while the other half, or what may be termed the ground engaging section may still be retained and its otherwise norm-a1 life be greatly prolonged.

A further object of the invention is to provide a renewable roller path and driving lug section having structural features, which lend themselves to manufacture of hardened alloy and shock resisting metal, thereby making it possible to save seventy-five percent of tread weight when the roller path and drive lugs are worn beyond repair.

With the above and other objects in view which will more readily appear as the nature of the invention is better understood, the same consists in the novel construction, combination, and arrangement of parts, hereinafter more fully described, illustrated, and claimed.

A preferred and practical embodiment of the invention is shown in the accompanying drawings in which:

FIGURE 1 is a detail sectional view of a preferred form of the new renewable roller path insert.

'FIGURE 2 is a perspective View of a crawler tread illustrating the renewable roller or tumbler engaging insert of FIG. 1 in the position about to be assembled to the tread.

FIGURE 3 is a perspective view of a modified form of a renewable roller path and drive lug insert and its related shoe, the said insert being provided with perforated ears intended to align with the pivot pin openings which connect adjacent tread units.

FIGURE 4 is a perspective view of the modified renewable roller path insert of FIG. 3 disassociated from the tread.

Similar reference characters designate corresponding parts throughout the several figures of the drawings.

A crawler tread unit or shoe designated generally as A is shown merely by way of illustration and may have any desired cross-section and body shape including a conventional ground engaging surface B.

However, as will be seen from FIGURES 1 and 2, the medial portion of the tread body, at the point where the same is to be engaged by the driving tumblers or idler rollers is provided with a special center area 1 between the spaced pivot pin receiving eyes 2, 2, at one side and the eyes. 3, 3 at the other side performing the same function.

This center area, in FIGS. 1 and 2, is provided with a plurality of spaced forwardly inclined recesses 4 which are formed at the time of casting or manufacture, the said recesses adapted to receive spaced mating inclined tenons or tongues 5 of the renewable roller path and driving lug engaging insert R. These fingers are disposed between the opposite outer wall portions 6 and 7 ('FIG. 1) of the tread body and are oblique to the ground engaging surface B of the tread. The tenons or tongues 5 constitute in effect a shank for securing the head of the insert R in the crawler tread.

It will also be apparent from FIGS. 1 and 2 that one end of the renewable insert, that is the end adjacent wall 7 of the tread, is provided with an enlarged knuckle portion 8 which fits between the adjacent eyes of the two pair of eyes 3-3, and has a bore 9 which aligns with the openings of the said pivot pin receiving eyes 3-3 to receive a conventional pivot pin like that shown at P, FIG. 2, for the eyes 2, 2.

The upper portion of the renewable insert R is provided with the upstanding lugs 10 intended to be engaged by the driving tumbler of the excavator unit in the well known manner, while the space between them provides a bearing path 10* for the treads of the rollers.

It will, of course, be understood that the tongues 5 engaging in the recesses 4 firmly engage because of the friction and weight of the excavator imposed on the crawler tread.

By way of illustrating the range of the invention, reference may be made to FIGURES 3 and 4 of the drawings which show a modification wherein the tread unit A has the general characteristics of the similar unit shown in FIGURE 1.

However, since the roller path and driving lug insert R is of modified construction, the body of the tread unit A is provided with a transverse opening 12 through walls 6 and 7 to receive a key 13 to lock the said unit R in place.

As in the previous case, the upper portion of the body 1 is provided with the upstanding drive lugs 10 and roller path 10 It may be further pointed out that in FIGURE 3 the recesses 14 are substantially of vertically wedge shape formation, as distinguished from being oblique as in FIGURES l and 2, thereby to receive the spaced intermediate tongues 15 arranged between opposite end walls 16 and 17, whose inner faces 16 and 17 are intended to embrace and fit against the opposite walls 6 and 7 of the body of the tread unit. The lower portions of the outer faces 19 and 20 of the insert are of partially arcuate or curved formation so as to clear or pass beneath the eyes of the ears 2, 2 and 3 3 to permit the usual tread connecting pivot pin (not shown) to be inserted in place without interference from the insert R.

While the curved portions of the outer walls 19 and 20 of the unit R would lie behind and, therefore, be held locked by the pivot pins for connecting each tread link nevertheless, to insure positive interlocking engagement aside from this feature and the wedging fit, it is preferred to provide the end walls 16 and 17 of the insert with openings 12 which register with the openings 12 in the body.

It will, of course, be understood that the tongues 15 have openings 12 which register with 12, and likewise, the webs of the body between the recesses 14 are provided with openings 12 which register with the opening 12 to receive the pin 13.

From the foregoing it will now be seen that the present invention provides a crawler tread unit or link to form an endless track whose medial portion receives a renewable roller path insert to be engaged either by the teeth of the driving tumbler or a crawler roller, thereby effecting considerable economy in the use of crawler treads. Because of the inclined disposition or pitch of the tongues or tenons of FIGS. 1 and 2, the insert will be firmly held in the tread. In all figures of the drawing it will be seen that the shoe A, often known as a shovel-tread, and the renewable unit R have mating inter-fitting mortise and tenon portions wherein the recesses constituting the mortises are arranged in spaced parallel relation transversely of the shoe and likewise the removable tread unit has tongue portions which are disposed transversely thereof and in spaced relation to be complementary to the recesses.

The renewable roller path R or R may be made of alloys which resist wear while the crawler tread itself may be made of ordinary steel or an alloy which, because of its cost of manufacture, is not as expensive as the alloy of which the renewable insert is made. Extraordinary economy both from the standpoint of time saved in servicing as well as greatly adding to the longevity of the tread units themselves is the practical and important result of the present invention.

I claim:

1. In a crawler tread unit, the combination, including, a ground engaging shoe provided with a plurality of spaced inclined recesses, a removable and replaceable roller path and driving section having spaced inclined tongie portions engaging in said recesses, and cooperating means on the shoe and renewable section for receiving a locking pin.

2. In a crawler tread unit, the combination, including a ground engaging shoe provided with a plurality of spaced inclined recesses, and also having spaced pivot pin receiving eyes at one edge, and a removable and replaceable roller path and driving section having spaced inclined tongues engaging in said recesses, and an offset knuckle portion at one side adapted to fit between said eyes and having an opening registering with said pivot pin receiving eyes.

3. In a crawler tread unit, the combination, including a ground engaging shoe having a central body portion provided with a plurality of spaced recesses, a removable Cfl and replaceable roller path section having spaced medially located tongue portions for engaging with said recesses and also having side walls for embracing the central body portion between the eyes, and cooperating means on the shoe body and the removable and replaceable roller path section for receiving a locking key.

4. In a tread unit for endless tracks, the combination comprising, a ground engaging shoe including a body provided with top and bottom walls and having a plurality of recesses in said top wall,

pairs of pivot pin receiving eyes at opposite edges of the shoe to receive pins for connecting one shoe with another,

and a removable and replaceable roller path unit having driving lugs on its upper face,

spaced tongue portions on the bottom face of the roller path unit for engaging with said recesses in the top wall of said shoe,

end walls for said unit adapted to embrace opposite side walls of the body of the shoe between each of said pair of eyes,

said end walls having their outer faces curved to clear the opposite eyes of each pair of eyes,

whereby, when pivot pins are inserted in each pair of eyes, said pivot pins will engage the curved portions of the end walls to hold the unit interlocked with the shoe.

5. In a tread unit according to claim 4, wherein,

the body of the shoe at the location of the recesses is provided with a pin receiving opening and the end walls and tongues of the renewable unit are provided with alined openings adapted to register with the opening in the shoe to receive a locking pin.

6. In a tread unit for endless tracks, the combination comprising,

a ground engaging shoe including a body having top and bottom walls and opposite pairs of spaced pin receiving eyes and a plurality of recesses in the body afiording unobstructed access from the top wall,

and a roller path unit having spaced tongues, said unit and tongues concurrently entering the recesses perpendicular to the top of said body,

and a locking portion of said roller path unit disposed between said eyes and having means registering therewith to receive a locking pin which also passes through said eyes to join one tread unit with an adjacent tread unit.

References Cited in the file of this patent UNITED STATES PATENTS 1,144,284 Bassett June 22, 1915 1,446,292 George Feb. 20, 1923 1,918,853 Masury July 18, 1933 2,133,653 Bomford et a1. Oct. 18, 1938 2,733,965 Gladden Feb. 7, 1956 2,797,967 Irvin July 2, 1957 FOREIGN PATENTS 551,512. France Jan. 9, 1923 765,965 France Mar. 31, 1934 

